How do I know my yoni Porutham?

The yoni porutham is tabulated by appointing one animal force to each such group e.g. if the boys nakshtra comes under a cat and the girls comes under rat then the yoni porutham of the couple is incompatible since the rat and the cat are enemies and so there is no possibility of the two living in compatible

What if Mahendra Porutham is not matching?

Mahendra Porutham is considered for the longevity, wealth and progeny. They consult the stars and horoscopes of the couple to find out what will be their future status in marriage, and if not found compatible, the marriage is called off.